Find the domain and the range of the relation and determine a value for x that makes the set not

Question

a function.
​{(10​,​5)​,(-8,​-3),(2​,​-1),(​5,​-7)}

(I already found the domain and range i just need to know a value for x that makes the set not a function)

SHOW WORK

Answer 1

If the same x value yields two or more different y values, then you
DON'T have a function.

All the values of x are different, so we can't tell. As it sits, it is a function.

Answer 2

but it says its not a function and i should answer (_, 12) and I have no idea what its supposed to mean??

Answer 3

nvm found the answer! its -8...
thanks for trying tho!